Looking for slim, adjustable antivirus software

I'm maintaining an obsolete 1 GHz XP system of a friend of mine. PC is mainly used for browsing (firefox), email, word processing, watching movies and (small) gaming. PC is behind a router w firewall.

W/o anti-virus software installed the performance of this system just meets the needs. Bottleneck is playback of (hi-res) highly compressed (divx, ...) movies, which can be a bit shaky, especially on the Internet (Youtube, Silverlight, ...).

I've tried several anti-virus programs on this system: AVG, Avast, Kaspersky (trial), ESET NOD (trial) and Avira. Biggest problems are at start-up, where these programs use a lot of resources (especially AVG).

I tried to leave the computer unprotected for at least half a year, but the other day it was infected by the annoying "XP Internet Security 2010"-virus, which made it impossible for my friend to access the internet until I came to the rescue.

So I'm looking for am AV-program which is:

Low on resources and can be configured in such a way that it only scans incoming software for virii: through emailing, browsing and downloading torrents, or from USB-sticks an CD-roms.

So no startup-scans and heuristic analyzing and the lot.

And no alarm bells ("Your system is at risk!") through pop ups and the like when not all of the options are enabled: this would make my friend very nervous.

Preferably free

The idea would be to perform a deep system scan manually once in a while and to keep the system clean by only checking newly imported software.

This is probably not the most secure setup, but would offer a reasonable level of protection at very low costs in terms of system performance. Every once in a while I make an image of the drive where XP lives, so in case of catching a real nasty virus, I can always roll back (documents and other data reside on a different drive).

have you tried BitDefender Free Edition? It seems to have on demand scanner- exactly what you need. Check it on their site. I haven't used it because I have the full Bitdefender version and I can say it is very good at removing Trojans. Good luck!

try nod32 antivirus it is very light, next is avira personal and kaspersky is light too

i would recommend u install avira business edition or nod32 antivirus

I tried the 3 of them. IMHO Avira is the lightest, especially at startup, but still not light enough for my taste. Problem is I can not configure either of them in the way I would like (no startup scan, just scan webtraffic, email and all new files (downloaded via web, P2P or USB).

Currently I have Avira running, and I'll keep with it untill I find something better.

have you tried BitDefender Free Edition? It seems to have on demand scanner- exactly what you need. Check it on their site. I haven't used it because I have the full Bitdefender version and I can say it is very good at removing Trojans. Good luck!

If it would be my own PC this would be perfect. Problem is that my friend and her daughter, who use the PC, are absolute noobs, so this wouldn't be a very safe solution. Besides that, I think some web traffic monitoring is needed as well..

If it would be my own PC this would be perfect. Problem is that my friend and her daughter, who use the PC, are absolute noobs, so this wouldn't be a very safe solution. Besides that, I think some web traffic monitoring is needed as well..

I see.. I recommended it because I believe it is very low on resources, however good luck ..if you find something, please share!